From edbc927b79c3b548d334f054f3d973e951d3e6de Mon Sep 17 00:00:00 2001
From: hippoz <10706925-hippoz@users.noreply.gitlab.com>
Date: Mon, 16 Jan 2023 17:44:45 +0200
Subject: [PATCH] add support for routing errors

---
 Makefile |  2 +-
 server.c | 14 +++++++-------
 wire.c   | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/Makefile b/Makefile
index 04614de..cbf9dc6 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ CFLAGS_RELEASE=-O2 -ggdb
 
 CFLAGS+=-pipe -Wall -Wextra -Wshadow -pedantic -std=c99
 
-CFLAGS+=$(CFLAGS_RELEASE)
+CFLAGS+=$(CFLAGS_DEV)
 
 jitterbug: util.c wire.c match.c server.c main.c
 	$(CC) $(CFLAGS) -o $@ $^
diff --git a/server.c b/server.c
index caab73a..517d6a7 100644
--- a/server.c
+++ b/server.c
@@ -224,10 +224,7 @@ int bus_client_assign_own_name(bus_t *s, int i, char *name)
         return -1;
     }
 
-    int name_index = bus_name_add(s, name, i);
-    if (name_index < 0) {
-        return -1;
-    }
+    int name_index = TRYST(bus_name_add(s, name, i));
     c->owned_name_index = name_index;
 
     return 0;
@@ -429,16 +426,19 @@ int handle_request_name(bus_t *s, int i, wire_message_t *msg, wire_context_t *ct
     }
 
     char *name = TRYPTR(wire_get_name_string(ctx));
-    TRYPTR(wire_get_u32(ctx)); // unused flags
+    uint32_t flags = *(uint32_t*)TRYPTR(wire_get_u32(ctx)); // unused flags
 
     char *name_str = TRYPTR(string_dup(name));
 
     int status_code = DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER;
 
     if (bus_client_assign_own_name(s, i, name_str) < 0) {
-        free(name_str);
         // TODO: report the actual error
         status_code = DBUS_REQUEST_NAME_REPLY_EXISTS;
+
+        WARN("client '%s' (index=%d) couldn't acquire name '%s'\n", s->names[s->clients[i].owned_name_index].name, i, name_str);
+
+        free(name_str);
     }
 
     _reply_begin("u") {
@@ -786,7 +786,7 @@ int bus_client_drain_messages(bus_t *s, int ci, uint8_t *data, uint32_t data_len
 #define _client_die(m) do { bus_client_error(s,i,m); continue; } while(0)
 int bus_turn(bus_t *s)
 {
-    static const char agree_unix_fd[] = "AGREE_UNIX_FD\r\n";
+    static const char agree_unix_fd[] = "ERROR\r\n";
     static const char auth_ok[] = "OK aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa\r\n";
     static const char auth_list[] = "REJECTED EXTERNAL\r\n";
     static const char auth_data[] = "DATA\r\n";
diff --git a/wire.c b/wire.c
index 2f69e92..fe40fe7 100644
--- a/wire.c
+++ b/wire.c
@@ -125,6 +125,7 @@ int wire_parse_message(wire_context_t *c, wire_message_t *msg)
             case DBUS_HEADER_FIELD_PATH: /* through */
             case DBUS_HEADER_FIELD_INTERFACE: /* through */
             case DBUS_HEADER_FIELD_MEMBER: /* through */
+            case DBUS_HEADER_FIELD_ERROR_NAME: /* through */
             case DBUS_HEADER_FIELD_DESTINATION: {
                 char *str = TRYPTR(wire_get_string(c));
                 VERBOSE("field: %s\n", str);
@@ -470,6 +471,37 @@ int wire_compose_unicast_reply(wire_context_t *c, wire_context_t *msg_c, wire_me
             // last element, don't align
         } break;
 
+        case DBUS_MESSAGE_ERROR: {
+            wire_message_field_t *reply_serial_field = &msg->fields[DBUS_HEADER_FIELD_REPLY_SERIAL];
+            wire_message_field_t *error_name_field = &msg->fields[DBUS_HEADER_FIELD_ERROR_NAME];
+            if (!reply_serial_field->present || !error_name_field->present) {
+                return -1;
+            }
+
+            TRYPTR(wire_set_u8(c, DBUS_HEADER_FIELD_REPLY_SERIAL));
+            TRYPTR(wire_set_signature(c, "u"));
+            TRYPTR(wire_set_u32(c, reply_serial_field->t.u32));
+            TRYPTR(wire_write_align(c, 8));
+
+            wire_message_field_t *signature_field = &msg->fields[DBUS_HEADER_FIELD_SIGNATURE];
+            if (signature_field->present) {
+                TRYPTR(wire_set_u8(c, DBUS_HEADER_FIELD_SIGNATURE));
+                TRYPTR(wire_set_signature(c, "g"));
+                TRYPTR(wire_set_signature(c, signature_field->t.str));
+                TRYPTR(wire_write_align(c, 8));
+            }
+
+            TRYPTR(wire_set_u8(c, DBUS_HEADER_FIELD_ERROR_NAME));
+            TRYPTR(wire_set_signature(c, "s"));
+            TRYPTR(wire_set_string(c, error_name_field->t.str));
+            TRYPTR(wire_write_align(c, 8));
+
+            TRYPTR(wire_set_u8(c, DBUS_HEADER_FIELD_SENDER));
+            TRYPTR(wire_set_signature(c, "s"));
+            TRYPTR(wire_set_string(c, sender_unique_name));
+            // last element, don't align
+        } break;
+
         default: {
             return -1;
         } break;